The 2019 Global Peace Index has ranked Iceland as the world's most peaceful nation for the 11th year in succession based on 23 factors including internal and external conflicts, military spending, terrorism, murder and other crime rates.

Afghanistan was at the bottom of the index, followed by Syria, South Sudan, Yemen and Iraq, according to the survey published on Tuesday by the Institute for Economics and Peace.

European nations formed 17 of the top 25 most peaceful countries, the study said.

Ukraine registered the biggest improvement since 2018, while Nicaragua showed the sharpest deterioration.

More than 400 million people live in areas with "low levels of peacefulness and high risk from climate change" with sub-Saharan Africa at greatest risk of environmental factors exacerbating conflicts, the study said.

Some 103 million people in eight of the least peaceful nations also live in "high climate hazard areas", it added.

Steve Killelea, the think-tank's founder, said "a deeper analysis (of the survey data) finds a mixture of positive and negative trends".

"Whilst the conflicts that have dominated the past decade, such as in Iraq and Syria, have begun to abate, new conflicts have emerged in Yemen, Nicaragua and Turkey, resulting in the bottom 10 countries in the index declining by more than the global average - increasing the global inequality in peace," Killelea said.

Australian Associated Press